GB945075A - Improvements relating to automatic vehicle guidance systems - Google Patents

Abstract

945,075. Inductive control of vehicles. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Oct. 16, 1962 [Nov. 24, 1961], No. 42144/61. Heading H4U. Control of a plough or other implement drawn by a vehicle is effected by two detectors, spaced apart on the vehicle in the direction of travel, when the detectors are in the vicinity of, and on opposite sides of, a transverse current carrying conductor. As described, six overlapping cable loops A-F, four of which are shown in Fig. 1, are buried below ploughing level in a field and supplied with H.F. alternating current through a selector switch SS. Initially only loop A is energized and a tractor T pulling a plough P carried on its left hand side a pick-up coil SH which so controls the steering SD that the tractor moves parallel to, but displaced to the right of, the right hand side of loop A. When, near point P, coils PH1, PH2 on the tractor are on either side of a transverse cable C2 energized at a different frequency, their outputs are effective through a diode phase detector, Fig. 3 (not shown), to operate means PA which lower the appropriate plough shares. In a similar manner, towards the end of the straight run near point T, the effect of a transverse cable C1 causes the shares to be raised and also changeover of the steering pickup coil to a right hand position 5 by moving coil SH or selecting another at the new position. The tractor then moves to the other side of cable as shown at X and returns parallel to but displaced to the other side of loop A, lowering and raising the plough shares when crossing cables C1, C2 as before. Changeover to pick-up coil position 2 then takes place and a further circuit is made. In all, changes of the steering pick-up coil between positions 1-5 result in five circuits of the field which overlap each other progressively towards the left. When, at the end of these five circuits, cables C1, C2 have been met 20 times a counter CO operates a H.F. A.C. transmitter TR on the tractor so that a fixed receiver R operates switch SS to transfer energization from loop A to loop B. Five more overlapping circuits are then made in the vicinity of loop B. Loops C-F are eventually energized in turn to produce further groups of five circuits to cover the whole field. Specification 932,266 is referred to.